title: Molybdenum Imido Alkylidene Metathesis Catalysts that Contain Electron Withdrawing Biphenolates or Binaphtholates.
abstract: We have prepared new Mo(NR)(CHCMe(2)Ph)(diolate) complexes (R = 2,6-i-Pr(2)C(6)H(3), 2,6-Me(2)C(6)H(3), 1-Adamantyl, or 2-CF(3)C(6)H(4)) that contain relatively electron-withdrawing binaphtholate (3,3'-bis-(9-anthracenyl), 3,3'-bispentafluorophenyl, or 3,3'-bis(3,5-bis(trifluoromethyl)phenyl) or biphenolate (3,3'-di-tert-butyl-5,5'-bistrifluoromethyl-6,6'-dimethyl-1,1'-biphenyl-2,2'-diolate) ligands. We also have prepared new monomeric Mo(NR)(CHCMe(2)Ph)(2,5-dimethylpyrrolide)(2) complexes and have treated them with biphenols or binaphthols in order to prepare several Mo(NR)(CHCMe(2)Ph)(diolate) species. In one case the new Mo(NR)(CHCMe(2)Ph)(diolate) complexes could be prepared only through reaction of a binaphthol [3,3'-bis(pentafluorophenyl)binaphthol] with a bis(2,5-dimethylpyrrolide) complex. The pyrrolide approach can be employed either to isolate catalysts on a preparative scale or to generate catalysts in situ. Several simple preliminary ring-closing metathesis reactions show that the new complexes are catalytically competent.
authors.affiliation: Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.
authors.forename: Rojendra
authors.initials: R
authors.lastname: Singh
authors.forename: Constantin
authors.initials: C
authors.lastname: Czekelius
authors.forename: Richard R
authors.initials: RR
authors.lastname: Schrock
authors.forename: Peter
authors.initials: P
authors.lastname: Müller
authors.forename: Amir H
authors.initials: AH
authors.lastname: Hoveyda